Conversion coating for cans containing hydrogen sulfide producing liquids

ABSTRACT

This disclosure relates to use of a conversion coating for reduction or prevention of hydrogen sulfide production in cans holding hydrogen sulfide producing liquids, such as wine. This disclosure also relates to metal cans comprising a conversion coating layer deposited on at least a portion of the inside surface of the metal can, a film-forming layer deposited on such conversion coating layer, and a hydrogen sulfide producing liquid deposited inside the metal can.

FIELD

The present disclosure relates in general to a metal can having a hydrogen sulfide liquid deposited therein, wherein the metal can comprises a conversion coating layer deposited on at least a portion of an inside surface thereof and a film forming layer.

BACKGROUND

Coatings are applied to numerous substrates to provide protective and/or decorative qualities. Certain liquids have sulfur dioxide and/or analogues such as metabisulphite added to stabilize the liquid and to prevent growth of unwanted bacteria and yeast. Other liquids may lead to the production of sulfur dioxide through metabolism of sulfur-containing amino acids or other organic processes. However, sulfur dioxide and/or analogues may cause production of volatile sulfur compounds (VSCs) such as hydrogen sulfide, H₂S, which create issues with respect to corrosion of the containers, “rotten egg” odor production, and tainting of the liquid in the metal cans. Thus, there is a desire for cans that would allow packaging of such liquids while reducing and/or eliminating the production of hydrogen sulfide and other VSCs.

SUMMARY

The present disclosure is directed to a metal can comprising a conversion coating layer deposited on at least a portion of an inside surface of the metal can, wherein the conversion coating layer comprises a lanthanide series element, a Group VIB metal, a Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; a film-forming layer deposited on at least a portion of the conversion coating layer; and a hydrogen sulfide producing liquid inside the metal can.

Also disclosed is a metal can comprising a conversion coating layer deposited on at least a portion of the inside surface of the metal can, wherein the conversion coating layer is deposited from a conversion coating composition comprising a lanthanide series element, a Group VIB metal, a Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; a film-forming layer deposited on at least a portion of the conversion coating layer; and a hydrogen sulfide producing liquid inside the metal can.

Also provided in this disclosure is a method of packaging a hydrogen sulfide producing liquid in a metal can, the method comprising depositing the hydrogen sulfide producing liquid inside the metal can, wherein the metal can comprises a conversion coating layer deposited on at least a portion of an inside surface of the metal can, wherein the conversion coating layer comprises a lanthanide series element, a Group VIB metal, a Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; and a film-forming layer deposited on at least a portion of the conversion coating layer.

The present disclosure also contemplates a metal can comprising a conversion coating layer deposited on at least a portion of an internal surface of the metal can, the conversion coating layer comprising a lanthanide series element, a Group VIB metal, a Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; a film forming layer deposited on at least a portion of the conversion coating layer; and a hydrogen sulfide producing liquid deposited inside the metal can, wherein the hydrogen sulfide producing liquid exhibits a hydrogen sulfide concentration of less than 35 ppb as measured by a gas detection tube for at least two months after the metal can is sealed.

DETAILED DESCRIPTION

According to the present disclosure, provided herein is a metal can comprising, or consisting essentially of, or consisting of, a conversion coating layer deposited on at least a portion of the inside surface of the metal can, wherein the conversion coating layer comprises a lanthanide series element, a Group VIB metal, Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; a film-forming layer deposited onto at least a portion of the conversion coating layer; and a hydrogen sulfide-producing liquid deposited inside the metal can.

A “conversion coating” layer, composition, or like terms, as used herein, refers to a self-supporting inorganic continuous or semi-continuous layer formed on the metal can surface via a chemical process that reacts with the metal can surface. A “continuous layer” refers to an unbroken layer of conversion coating formed on the whole substrate surface. A “semi-continuous layer” is one that is broken; that is, the layer is not continuous across the whole surface.

Without intending to be bound by theory, it is believed that the conversion coating layer disclosed herein reduces the oxidation of the metal substrate of the can by the hydrogen sulfide producing liquid, thereby preventing and/or reducing the subsequent reduction of the sulfur dioxide and other sulfur compounds in the hydrogen sulfide producing liquid which lead to hydrogen sulfide production. Inhibiting such reactions between the metal of the can and the free sulfide dioxide in the hydrogen sulfide producing liquid is believed to reduce and/or prevent corrosion of the metal can and tainting of the hydrogen sulfide producing liquid, such as, without limitation, wine, deposited within.

The term “metal can” includes any type of metal can, container or any type of receptacle or portion thereof that is sealed by the content manufacturer (e.g. food and/or beverage manufacturer) to minimize or eliminate spoilage of the contents until such metal can is opened by the consumer. The cans can include “two piece cans” and “three-piece cans” as well as drawn and ironed one-piece cans; such one piece cans often find application with aerosol products. The metal can may be a food and/or beverage can. The metal can may be a monobloc aerosol can and/or tube. Suitable examples of monobloc aerosol cans and/or tubes include, but are not limited to, deodorant and hair spray containers. The metal can may be a metal can bottle.

The metal can may be formed from any suitable material. Suitably, the metal can comprises metal substrates, metal alloy substrates, and/or substrates that have been metallized, such as nickel plated plastic. Suitable examples include, but are not limited to, the following: steel; tinplate; tinplate pre-treated with a protective material such as chromium, titanium, titanate or aluminum; tin-free steel (TFS); galvanised steel, such as for example electro-galvanised steel; aluminum; aluminum alloy; and combinations thereof.

The metal or metal alloy may comprise or be steel, aluminum, magnesium, and/or alloys thereof. For example, the steel substrate may be cold rolled steel, hot rolled steel, electrogalvanized steel, and/or hot dipped galvanized steel. Aluminum alloys of the 1XXX, 2XXX, 3XXX, 4XXX, 5XXX, 6XXX, or 7XXX series as well as clad aluminum alloys also may be used as the substrate. Aluminum alloys may comprise 0.01% by weight copper to 10% by weight copper. Aluminum alloys which are treated may also include castings, such as 1XX.X, 2XX.X, 3XX.X, 4XX.X, 5XX.X, 6XX.X, 7XX.X, 8XX.X, or 9XX.X (e.g.: A356.0). For example, the metal can may comprise aluminum alloy in the 3XXX series, such as aluminum alloy AA3104, AA3003, AA3004, AA3005, and/or AA5XXX series. Magnesium alloys of the AZ31B, AZ91C, AM60B, or EV31A series also may be used as the substrate. Additionally, substrates may comprise non-metal conductive materials including composite materials such as, for example, materials comprising carbon fibers or conductive carbon. The substrate may also comprise other suitable non-ferrous metals such as titanium or copper, as well as alloys of these materials.

It will be appreciated by a person skilled in the art that the can body and can end of the metal can may be formed from the same or different materials, such as the same or different metals. Suitably, the can body and can end of the metal can may be formed from the same material, such as the same metal.

The can body and/or can end may be made from coiled metal stock. Suitably, at least the can end may be formed from coiled metal stock. Suitably, the conversion coating compositions of the present invention may be applied to coiled metal stock, such as the coiled metal stock from which the ends of cans are made (“can end stock”).

The conversion coating composition may be applied to the can end stock prior to the can end being cut and stamped out of the coiled metal stock. The can ends having a score line thereon may be “easy open” can ends, sometimes referred to as “easy open ends” or even “EOEs”. Suitably, the score line is applied to the can ends after the can ends have punched from the coated metal stock. The can ends, once formed, are suitably attached to a can body. The can end may be attached to the can body by any suitable method. Suitably, the can end may be attached to the can body by an edge rolling process.

The coating compositions may be applied to substantially all of or to a portion of the interior surface of the can end. For example, the coating compositions may be applied to at least a portion of the interior surface of the can end over at least a portion of the score line. The conversion coating composition may be applied to at least the internal surface of the can end over a portion of the score line or may be applied over all of the score line. Suitably, the coating compositions may be applied to substantially all of the interior surface of the can end.

As stated above, the metal can comprises a conversion coating layer deposited on at least a portion of the inside surface of the metal can, wherein the conversion coating layer comprises a lanthanide series element, a Group VIB metal, Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2. The conversion coating layer may be deposited on at least a portion of an internal surface of a can body and/or a can end of the metal can.

As described in more detail below, the conversion coating layer may be formed from a conversion composition comprising, or consisting essentially of, or consisting of, a lanthanide series element, a Group VIB metal, a Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2.

The lanthanide series element may comprise cerium, praseodymium, terbium, and/or alloys thereof. The Group IIIB metal may comprise yttrium, scandium, and/or alloys thereof. The Group IVB metal may comprise zirconium, titanium, hafnium, and/or alloys thereof. The Group VIB metal may comprise chromium (III), chromium (VI), molybdenum, and combinations thereof.

The conversion coating layer may comprise a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2. Any of the monomeric subunits m1 and m2 described herein may be useful in the conversion coating layer. For example, where the metal can comprises aluminum and/or aluminum alloy, the conversion coating layer is formed when aluminum oxide on the surface forms esters with phosphate or phosphonic groups (Al—O—P bonds) of the homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2.

The copolymer may be a dipolymer, a terpolymer, or a higher polymer. The homopolymer or copolymer may be a statistical or a block homopolymer or copolymer and may be formed by radical continuous or batchwise polymerization.

As used herein, the terms “homopolymer” and “homopolymer comprising monomeric subunits m1,” when used with respect to the homopolymer disclosed herein, refers to a homopolymer resulting from the polymerization of one kind of monomer m1, wherein the homopolymer does not comprise any other monomeric subunits.

As used herein, the terms “copolymer,” when used with respect to the present invention, refers to a dipolymer or higher copolymer resulting from the polymerization of at least one kind of monomer m1 and at least one kind of monomer m2 or at least two kinds of monomers m1. For clarity, “copolymer” includes dipolymers, terpolymers, and higher copolymers.

As used herein, the terms “dipolymer,” when used with respect to the copolymer of the present invention, refers to a copolymer resulting from the polymerization of one kind monomer m1 and one kind of monomer m2 or two kinds of monomers m1.

As used herein, the terms “terpolymer,” when used with respect to the present invention, refers to a copolymer resulting from the polymerization of three monomeric subunit types, where at least one monomer is m1.

Suitable examples of the phosphorous-containing monomeric subunits m1 include organophosphorous compounds containing phosphates, phosphate salts, and/or phosphate esters, phosphonic acids, phosphonic acid salts, and/or phosphonic esters, and/or phosphinic acids, phosphinic acid salts, and/or phosphinic esters. Examples include, but are not limited to, vinyl phosphonic acid, dimethyl vinyl phosphonate, diethyl vinyl phosphonate, r other dialkyl vinyl phosphonates, maleic acid dimethyl phosphonate, maleic acid diethyl phosphonate, phosphate-, phosphonate-, or phosphinate-substituted methacrylate or acrylate monomers, phosphate-, phosphonate-, or phosphinate-substituted acrylamide monomers, or other monomers containing phosphorus-containing substituents and a polymerizable bond.

As used herein, the term “(meth)acrylic acid,” when used with respect to the monomeric units, refers to acrylic and/or methacrylic acid subunits.

As used herein, the term “(meth)acrylate” refers to an acrylate, a methacrylate, or a mixture of acrylate and methacrylate.

Suitable examples of phosphorous-containing monomeric subunits m1 include those comprising the structure of Formula I:

wherein R₁ and R₂ comprise hydrogen, a cation, an alkyl radical, an aryl radical, or a phosphoester group, and R₃ comprises an organic linking group terminating in an atom that is covalently bonded to an atom present in the addition polymer backbone. The organic linking group may comprise at least one carbon atom, and may comprise additional functional groups, such as, for example, one or more ether, amine, or hydroxyl functional groups, among other functional groups, and at least a portion of the organic linking group may comprise a polyether if at least two ether groups are present. The organic linking group may comprise an organic chain, and the organic chain may terminate in a carbon atom on either side of the chain.

Other suitable examples of phosphorous-containing monomeric subunits m1 include those comprising the structure of Formula II:

wherein R₁ and R₂ comprises hydrogen, a cation, an alkyl radical, an aryl radical, or a phosphoester group, wherein R₁ and R₂ may be the same or different, and wherein R₃ comprises an organic linking group terminating in an atom that is covalently bonded to a carbon atom present in the addition polymer backbone. The organic linking group may comprise at least one carbon atom, and may comprise additional functional groups, such as, for example, one or more ether, amine, or hydroxyl functional groups, among other functional groups, and at least a portion of the organic linking group may comprise a polyether if at least two ether groups are present. The organic linking group may comprise an organic chain, and the organic chain may terminate in a carbon atom on either side of the chain.

Further suitable examples of phosphorous-containing monomeric subunits m1 include those comprising the structure of Formula III:

wherein R₁ comprises hydrogen, a cation, an alkyl radical, an aryl radical, or a phosphoester group, R₂ comprises hydrogen, an alkyl radical, or an aryl radical, and R₃ comprises an organic linking group terminating in an atom that is covalently bonded to an atom present in the addition polymer backbone. The organic linking group may comprise at least one carbon atom, and may comprise additional functional groups, such as, for example, one or more ether, amine, or hydroxyl functional groups, among other functional groups, and at least a portion of the organic linking group may comprise a polyether if at least two ether groups are present. The organic linking group may comprise an organic chain, and the organic chain may terminate in a carbon atom on either side of the chain.

Further suitable examples of phosphorus-containing monomeric subunits m1 include those comprising a polymerizable double bond and a phosphorus containing functional group such as a phosphine, phosphine oxide, phosphonium salt, or phosphate amide.

Monomeric subunit m2 may be any non-phosphorous-containing monomer that is capable of co-polymerizing with monomer subunits m1. For example, m2 may be a carboxylic acid- or anhydride-containing monomeric subunit.

Monomeric subunit m2 may be an acid or anhydride functional ethylenically unsaturated monomer. Suitable examples of monomeric subunits m2 include methacrylic acid, acrylic acid, maleic acid or its anhydride, fumaric acid, itaconic acid or its anhydride.

Monomeric subunit m2 also may be a (meth)acrylate. Suitable examples of (meth)acrylate monomeric subunits m2 include alkyl esters of (meth)acrylic acid. Non-limiting examples of alkyl esters of (meth)acrylic acid include methyl (meth)acrylate, ethyl (meth)acrylate and propyl (meth)acrylate. Other suitable examples of monomeric subunit m2 include (meth)acrylamides, such as N-isopropyl acrylamide, esters of maleic acid, fumaric acid, or itaconic acid, vinyl monomers such as styrenics, such as styrene sulfonic acid, vinyl ethers, or other monomers containing a polymerizable double bond, such as N-vinylpyrrolidone.

In an example, the copolymer disclosed herein may include a dipolymer comprising subunits m1 and m2 and having the structure of Formula IV:

where x varies from greater than 5 to 100 mol % and y varies from 0 to 95 mol %.

Monomeric subunit m1 may be present in the homopolymer or copolymer in an amount of at least 5 molar percent based on total molarity of the homopolymer or copolymer, such as at least 20 molar percent, such as at least 40 molar percent, and may, in some instances, be present in the homopolymer or copolymer an amount of 100 molar percent based on total molarity of the homopolymer or copolymer, such as no more than 80 molar percent, such as no more than 70 molar percent. Monomeric subunit m1 may be present in the homopolymer or copolymer in an amount of 5 molar percent to 100 molar percent based on total molarity of the homopolymer or copolymer, such as 20 molar percent to 80 molar percent, such as 40 molar percent to 70 molar percent.

Monomeric subunit m2 may be absent from the homopolymer or copolymer. Monomeric subunit m2 may be present in the homopolymer or copolymer disclosed herein, if at all, in an amount of at least 0.1 molar percent based on total molarity of the homopolymer or copolymer, such as at least 20 molar percent, such as at least 30 molar percent, and may, in some instances, be present in the homopolymer or copolymer an amount of 95 molar percent based on total molarity of the homopolymer or copolymer, such as at least 80 molar percent, such as at least 30 molar percent. Monomeric subunit m2, if present at all, may be present in the homopolymer or copolymer in an amount of 0.1 molar percent to 95 molar percent based on total molarity of the homopolymer or copolymer, such as 20 molar percent to 80 molar percent, such as 30 molar percent to 60 molar percent.

The homopolymer or copolymer, if present at all, may be present in the conversion coating composition in an amount of at least 100 ppm based on total weight of the conversion coating composition, such as at least 150 ppm, such as at least 300 ppm, such as at least 400 ppm, and may, in some instances, be present in the conversion coating composition in an amount of no more than 3000 ppm based on total weight of the conversion coating composition, such as no more than 1000 ppm, such as no more than 750 ppm, such as no more than 600 ppm. The homopolymer or copolymer, if present at all, may be present in the conversion coating composition in an amount of 100 ppm to 3000 ppm based on total weight of the conversion coating composition, such as 150 ppm to 1000 ppm, such as 300 ppm to 750 ppm, such as 400 ppm to 600 ppm.

The conversion coating composition and/or the conversion coating layer formed therefrom may further comprise a Group IA metal, a Group IIA metal, a Group VB metal, a Group VIIB metal, and/or a Group XII metal. The Group IA metal may comprise lithium. The Group IIA metal may comprise magnesium. The Group VB metal may comprise vanadium. The Group VIIB metal may comprise manganese. The Group XII metal may comprise zinc.

When a continuous or semi-continuous conversion coating layer is formed on the substrate surface, the layer can have a thickness that is uniform or a thickness that is variable; that is, the layer may have a different thickness at different locations on the treated substrate. The average thickness of the conversion coating layer on the metal surface may be 0.05 mg/square inch (msi) or less, such as 0.001 msi to 0.05 msi, 0.001 msi to 0.04 msi, 0.001 msi to 0.03 msi, 0.001 msi to 0.02 msi, 0.01 msi to 0.05 msi, or 0.01 msi to 0.02 msi or any other range combination using these endpoints. For example, the average thickness of the conversion coating layer on the metal surface may be 0.05 msi, 0.04 msi, 0.02 msi, 0.01 msi, 0.005 msi, or 0.001 msi. The average thickness, as disclosed herein, is determined by using a stripping solution of known volume to remove the conversion coating from a piece of the coated can of known area and then measuring the zirconium concentration in the solution by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The concentration of zirconium is then converted to msi (mg per square inch) and determined to be the thickness of the conversion coating layer.

The film-forming layer can be deposited from a film forming composition. Any suitable film forming composition can be used according to the present invention. As used herein, the term “film forming composition” refers to a composition, typically comprising one or more film-forming resins, that can form a self-supporting continuous or semi-continuous film on at least a horizontal surface of a substrate upon removal of any diluents or carriers present in the composition or upon curing at ambient or elevated temperature. Conventional film-forming resins that may be used include, without limitation, those typically used in packaging coating compositions. The film forming composition may comprise a thermosetting film forming resin or a thermoplastic film forming resin. As used herein, the term “thermosetting” refers to resins that “set” irreversibly upon curing or crosslinking, wherein the polymer chains of the polymeric components are joined together by covalent bonds. This property is usually associated with a crosslinking reaction of the composition constituents often induced, for example, by heat or radiation. Curing or crosslinking reactions also may be carried out under ambient conditions. Once cured or crosslinked, a thermosetting resin will not melt upon the application of heat and is insoluble in solvents. As used herein, the term “thermoplastic” refers to resins that comprise polymeric components that are not joined by covalent bonds and thereby can undergo liquid flow upon heating and are soluble in solvents.

Ambient conditions generally refer to room temperature and humidity conditions or temperature and humidity conditions that are typically found in the area in which the composition is applied to a substrate, e.g., at 10° C. to 40° C. and 5% to 80% relative humidity, such as at 20° C. to 40° C. and 20% to 80% relative humidity, while elevated temperatures are temperatures that are above ambient temperature.

The film forming composition may comprise any of a variety of polymers well-known in the art. Generally, these polymers may be any polymers of these types made by any method known to those skilled in the art. The film forming composition may comprise, for example, an acrylic polymer, a polyester polymer, a phenolic resin, an epoxy resin, an epoxy mimic, a laminate, a polyurethane polymer, a polyamide polymer, polyvinyl chloride (PVC) resins, alkyd resins, a polyether polymer, a polysiloxane polymer, and/or copolymers thereof. The film-forming composition may comprise a phenolic resin, an epoxy resin, a polyester polymer, an acrylic polymer, and/or a polyolefin polymer. The film-forming composition may comprise an acrylic polymer. The film forming layer may comprise a phenolic, an epoxy, a polyester, an acrylic, and/or a polyolefin. The film forming composition may comprise an emulsion polymerized latex acrylic material, a solution polymerized latex acrylic material, amine epoxy polymerized material, or a combination thereof. For example, the film forming composition may comprise a core shell acrylic latex.

The functional groups on the film forming resin may be selected from any of a variety of reactive functional groups, including, for example, carboxylic acid groups, amine groups, epoxide groups, hydroxyl groups, thiol groups, carbamate groups, amide groups, urea groups, isocyanate groups (including, without limitation, blocked isocyanate groups), mercaptan groups, and combinations thereof.

The film forming layer on the metal can may have any suitable dry film thickness. For example, the film forming layer may have a dry film thickness of greater than 2 microns (μm), greater than 5 μm, greater than 10 μm, less than 40 μm, less than 30 μm, less than 20 μm, or a range combination using these endpoints. For example, the dry film thickness may be 2 μm to 40 μm, 2 μm to 30 μm, 2 μm to 20 μm, 5 μm to 40 μm, 5 μm to 30 μm, 5 μm to 20 μm, or the like. The dry film thickness of the film forming layer is determined using a SENCON S19600 Coating Thickness Gauge.

By “hydrogen sulfide producing liquid” as used herein, it is meant liquids which, before being deposited in the metal can, include at least 1 part per million (ppm) of a sulfur source, e.g. sulfites, and in which reactions between the uncoated metal substrate and sulfur source produces hydrogen sulfide. For example, the hydrogen sulfide producing liquid comprises at least 5 ppm, at least 7 ppm, at least 10 ppm, at least 30 ppm, at least 50 ppm, and/or less than 100 ppm, less than 70 ppm, less than 50 ppm of a sulfur source. For example, the hydrogen sulfide producing liquid comprises 5 ppm to 100 ppm of a sulfur source, such as 7 ppm to 70 ppm, such as 10 ppm to 50 ppm, such as 30 ppm to 50 ppm. One skilled in the art would understand that the sulfur can be detected using a variety of known methods, including, without limitation, ion selective electrodes, gas chromatograph with a sulfur chemoluminescence detector, and/or gas detection tube. Values herein are provided using the gas detection tube method described herein.

The hydrogen sulfide producing liquid deposited in the metal can may comprise wine, beer, cider, cocktails, kombucha, fruit juice, vinegar, cordial, coconut milk, soft drink, mead, perfume, body spray, or any other liquid in which reactions between the uncoated metal substrate and sulfur source produces hydrogen sulfide.

In recent years, there has been a renewed interest in packaging wine in cans. Wine is produced by the yeast fermentation of the juice of grapes and occasionally other fruits. As part of the control processes for the fermentation and handling of wine, sulfur dioxide and/or analogues such as metabisulphite are often added to wine to stabilize the wine and to prevent growth of unwanted bacteria and yeast. Accordingly, the hydrogen sulfide producing liquid deposited in the metal can may comprise wine. The wine may comprise sparkling wine, red wine, white wine, or rosé wine.

Also provided in this disclosure is a metal can comprising a conversion coating layer deposited on at least a portion of the inside surface of the metal can, wherein the conversion coating layer is deposited from a conversion coating composition comprising a lanthanide series element, a Group VIB metal, a Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; a film-forming layer deposited on at least a portion of the conversion coating layer; and a hydrogen sulfide producing liquid deposited inside the metal can such that an internal surface of the can is at least partially in contact with the hydrogen sulfide-producing liquid.

The conversion coating composition may comprise a source of the lanthanide series element, Group VIB metal, Group IIIB metal, and/or Group IVB metal present in the conversion coating layer. For example, the Group IVB metal in the conversion coating layer may comprise zirconium. Suitable sources of the zirconium in the conversion coating composition include, but are not limited to, hexafluorozirconic acid, alkali metal and ammonium salts thereof, ammonium zirconium carbonate, zirconyl nitrate, zirconyl sulfate, zirconium carboxylates and/or zirconium hydroxycarboxylates, such as acid hydrofluorozirconic, zirconium acetate, zirconium oxalate, ammonium zirconium glycolate, ammonium zirconium lactate, and/or zirconium ammonium citrate. For example, the source of the zirconium in the conversion coating composition may comprise hexafluorozirconic acid.

The Group IVB metal also may be titanium and/or hafnium. Suitable sources of the titanium compounds include, but are not limited to, fluorotitanic acid and/or its salts. A suitable source of the hafnium compound includes, but is not limited to, hafnium nitrate.

The Group VIB metal may comprise molybdenum and/or chromium. A suitable source of molybdenum in the conversion coating composition may be in the form of a salt. Suitable molybdenum salts may include sodium molybdate, calcium molybdate, potassium molybdate, ammonium molybdate, molybdenum chloride, molybdenum acetate, molybdenum sulfamate, molybdenum formate, and/or molybdenum lactate. Suitable sources of chromium may include chromium (III) and/or chromium (VI).

As mentioned above, the conversion coating composition of the present invention may comprise a trivalent chromium cation. The conversion coating composition may further comprise an anion that may be suitable for forming a salt with the trivalent chromium cation, including for example a sulfate, a nitrate, an acetate, a carbonate, a hydroxide, or combinations thereof.

The conversion coating composition may exclude hexavalent chromium or compounds that include hexavalent chromium. Non-limiting examples of such materials include chromic acid, chromium trioxide, chromic acid anhydride, dichromate salts, such as ammonium dichromate, sodium dichromate, potassium dichromate, and calcium, barium, magnesium, zinc, cadmium, and strontium dichromate. When a conversion coating composition and/or a coating or a layer, respectively, formed from the same is substantially free, essentially free, or completely free of hexavalent chromium, this includes hexavalent chromium in any form, such as, but not limited to, the hexavalent chromium-containing compounds listed above.

Thus, optionally, according to the present invention, the conversion compositions and/or coatings or layers, respectively, deposited from the same may be substantially free, may be essentially free, and/or may be completely free of one or more of any of the elements or compounds listed in the preceding paragraph. A conversion coating composition and/or coating or layer, respectively, formed from the same that is substantially free of hexavalent chromium or derivatives thereof means that hexavalent chromium or derivatives thereof are not intentionally added, but may be present in trace amounts, such as because of impurities or unavoidable contamination from the environment. In other words, the amount of material is so small that it does not affect the properties of the conversion composition; in the case of hexavalent chromium, this may further include that the element or compounds thereof are not present in the conversion compositions and/or coatings or layers, respectively, formed from the same in such a level that it causes a burden on the environment. The term “substantially free” means that the conversion coating composition and/or coating or layers, respectively, formed from the same contain less than 10 ppm of any or all of the elements or compounds listed in the preceding paragraph, based on total weight of the composition or the layer, respectively, if any at all. The term “essentially free” means that the conversion coating composition and/or coatings or layers, respectively, formed from the same contain less than 1 ppm of any or all of the elements or compounds listed in the preceding paragraph, if any at all. The term “completely free” means that the conversion coating composition and/or coatings or layers, respectively, formed from the same contain less than 1 ppb of any or all of the elements or compounds listed in the preceding paragraph, if any at all.

The conversion coating composition may further comprise a source of phosphate ions. The source of phosphate ions may comprise phosphoric acid, such as 75% phosphoric acid, monosodium phosphate and/or di sodium phosphate.

The source of phosphate ions may be present in the conversion coating composition in an amount of 2 ppm to 300 ppm, such as 25 ppm to 100 ppm based on the total weight of the ingredients in the conversion coating composition. The conversion coating composition may comprise a source of phosphate ions in an amount of 100 ppm to 300 ppm, 100 ppm to 200 ppm, 110 ppm to 200 ppm, 120 ppm to 180 ppm, or, in some cases, 140 ppm to 180 ppm.

The conversion coating composition may further comprise a source of free fluoride. As used herein, the term “free fluoride” refers to isolated fluoride ions. The source of free fluoride in the conversion coating composition may derive from the source of the lanthanide series element, Group VIB metal, Group IIIB metal, and/or Group IVB metal used in the conversion coating composition. The source of free fluoride in the conversion coating composition may derive from the source of the Group VIB metal used in the conversion coating composition, such as, for example, hexafluorozirconic acid and/or hexafluorotitanic acid and salts thereof. As the Group IVB metal is deposited upon the metal substrate of the can upon applying the conversion coating composition on at least a portion of the inside surface of the metal can, fluorine in the hexafluorozirconic acid and/or hexafluorotitanic acid will become free fluoride and the level of free fluoride in the conversion coating composition will, if left unchecked, increase with time as metal is treated with the conversion coating composition.

The lanthanide series element, Group VIB metal, Group IIIB metal, and/or Group IVB metal used in the conversion coating composition that forms the conversion coating may be present as the fluometallate ion, e.g., ZrF₆ ⁻. As this fluometallate ion reacts with the substrate and the component hydrolyzes to form the oxide, fluoride ions can be released as free fluoride. As more fluoride ions are released to the bath and the free fluoride level increases, the equilibrium of the deposition reaction starts to move away from oxide formation back in the direction of the fluometallate ion; in other words, the solubility of the component increases and it becomes more difficult to form the conversion coating film.

In examples, the source of free fluoride may comprise one of the Group IVB metal compounds described above. In other examples, the source of free fluoride may comprise a compound other than the lanthanide series element, Group VIB metal compound, Group IIIB metal compound, and/or Group IVB metal compound. The source of free fluoride may comprise any fluoride-containing compound including monofluorides, bifluorides, fluoride complexes, and mixtures thereof known to generate fluoride ions. Non-limiting examples of such sources include 1-IF, NH4F, NFI4HF2, NaF, and NaHF2. Examples also include ammonium and alkali metal fluorides, acid fluorides, fluoroboric, fluorosilicic, fluorotitanic, and fluorozirconic acids and their ammonium and alkali metal salts, and other inorganic fluorides, non-limiting examples of which are: zinc fluoride, zinc aluminum fluoride, titanium fluoride, zirconium fluoride, nickel fluoride, ammonium fluoride, sodium fluoride, potassium fluoride, and hydrofluoric acid, as well as other similar materials known to those skilled in the art. Water-soluble fluoride compounds may be utilized to introduce the free fluoride. Suitable fluoride compounds include alkali metal fluorides such as sodium fluoride, ammonium fluoride salts such as ammonium fluoride and ammonium bifluoride, other inorganic fluoride salts such as sodium silicofluoride, ammonium silicofluoride, hydrofluoric acid, hydrofluorosilicic acid, such as 23% hydrofluorosilicic acid, and fluoboric acid, such as 50% fluoboric acid.

The free fluoride may be present in the conversion coating composition in an amount of 5 ppm to 300 ppm, such as 25 ppm to 100 ppm based on the total weight of the ingredients in the conversion coating composition. The conversion coating composition may comprise free fluoride in an amount of 100 ppm to 300 ppm free fluoride, 100 ppm to 200 ppm free fluoride, 110 ppm to 200 ppm free fluoride, 120 ppm to 180 ppm free fluoride, or, in some cases, 140 ppm to 180 ppm free fluoride. The free fluoride ions may be present in the conversion coating composition in a weight ratio of free fluoride ions to the Group VIB metal, Group IIIB metal and/or Group IVB metal of 40 to 1, and in some cases, 8 to 1.

At application, the conversion coating composition may have a pH of less than 7, and in some cases the pH may be within the range of 1 to 6, such as 1.5 to 5.5. The pH of the conversion coating composition may be maintained through the inclusion of pH adjusters, such as an acid and/or a base. The pH may be adjusted using mineral acids, such as hydrofluoric acid, fluoboric acid and/or phosphoric acid; organic acids, such as lactic acid, acetic acid, citric acid, tannic acid, and/or sulfamic acid; and/or water soluble or water dispersible bases, such as sodium hydroxide, ammonium hydroxide, ammonia, or amines such as triethylamine, and/or methylethyl amine. The pH may also be adjusted using inorganic acids such as, for example, sulfuric acid, hydrochloric acid, and/or nitric acid.

The pH adjusters may be in the conversion coating composition in an amount of 0.01% w/w to 10% w/w of the conversion coating. For example, the acid and/or base may be in an amount of 0.01% w/w to 9% w/w, 0.01% w/w to 8% w/w, 0.01% w/w to 7% w/w, 0.01% w/w to 6% w/w, 0.01% w/w to 5% w/w, 0.02% w/w to 10% w/w, 0.02% w/w to 9% w/w, 0.02% w/w to 8% w/w, 0.02% w/w to 7% w/w, 0.02% w/w to 6% w/w, 0.02% w/w to 5% w/w, 0.03% w/w to 10% w/w, 0.03% w/w to 9% w/w, 0.03% w/w to 8% w/w, 0.03% w/w to 7% w/w, 0.03% w/w to 6% w/w, or 0.03% w/w to 5% w/w.

The conversion coating composition may also include a sequestering and/or chelating agent, such as, for example, sodium gluconate. Sodium gluconate may also be included in the conversion coating composition to prevent staining on bright aluminum.

The conversion coating composition may further comprise an electropositive metal. The electropositive metal may comprise copper, nickel, silver, gold, and combinations thereof. The electropositive metal may comprise copper. The copper may comprise copper nitrate, copper sulfate, copper chloride, copper carbonate, or copper fluoride. The electropositive metal may comprise from greater than 0 to 150 parts per million (ppm) based on a total weight of the ingredients in the conversion coating composition. For example, the electropositive metal may be present in the conversion composition in an amount of at least 2 ppm based on total weight of the ingredients in the conversion coating composition, such as at least 10 ppm, such as at least 50 ppm, such as at least 75 ppm, such as at least 100 ppm, and may be present in an amount of no more than 150 ppm. For example, the electropositive metal may comprise 2 ppm to 150 ppm, 10 ppm to 150 ppm, 50 ppm to 150 ppm, 75 ppm to 150 ppm, 100 ppm to 150 ppm, based on a total weight of the ingredients in the conversion coating composition.

For example, the conversion coating composition may comprise hexafluorozirconic acid as a source of Group VIB metal as well as a source of free fluoride, hydrofluorosilicic acid and fluoboric acid as a source of free fluoride, phosphoric acid as a source of phosphate ions, sodium gluconate as the sequestering agent, nitric acid, aqueous ammonia, and tannic acid as pH adjusters, and deionized water. In another example, the coating composition may comprise hexafluorozirconic acid as a source of the Group VIB metal, phosphoric acid as the source of phosphate ions, copper nitrate as the electropositive metal, and deionized water.

The present disclosure is also directed to a method of packaging a hydrogen sulfide producing liquid in a metal can, the method comprising depositing the hydrogen sulfide producing liquid inside the metal can, wherein the metal can comprises a conversion coating layer deposited on at least a portion of the inside surface of the metal can, wherein the conversion coating layer comprises a lanthanide series element, Group VIB metal, Group IIIB metal, Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; and a film-forming layer deposited on at least a portion of the conversion coating layer.

The conversion coating composition disclosed herein may be applied to a metal substrate, such as at least a portion of an internal surface of a can body and/or a can end of the metal can. Any suitable technique may be used to apply the conversion coating composition onto the substrate, including, for example, brushing, dipping, flow coating, spraying and the like. In some instances, however, such depositing of the conversion composition may comprise an electrocoating step wherein an electrodepositable composition is deposited onto a metal substrate by electrodeposition. For example, the conversion coating composition may be applied as a spray. Suitably, a pump may draw the conversion coating composition out of a tank/bath through the spray risers, and after spraying onto the substrate, the excess conversion coating composition drains back into the tank/bath.

After the substrate is contacted with the conversion coating composition, a film-forming composition may be deposited onto at least a portion of the surface of the substrate that has been contacted with the conversion coating composition. Any suitable technique may be used to deposit such a film forming composition onto the substrate, including, for example, brushing, dipping, flow coating, spraying and the like. In some instances, however, such depositing of the film forming composition may comprise an electrocoating step wherein an electrodepositable composition is deposited onto a metal substrate by electrodeposition. In certain other instances, such depositing of a film forming composition comprises a powder coating step. The depositing of a film forming composition could be a laminate. In still other instances, the film forming composition may be a liquid coating composition.

The method may further comprise applying the film forming composition to form the film forming layer onto at least a portion of the metal can having the conversion coating composition deposited thereon. The method may further comprise applying a coating derived from the film forming composition to form the film forming layer onto at least a portion of the metal can having the conversion coating composition deposited thereon.

The film forming composition may be cured by any suitable method. The film forming composition may be cured by heat curing, radiation curing, or by chemical curing, such as by heat curing. The film forming composition, when heat cured, may be cured at any suitable temperature. The film forming composition, when heat cured, may be cured to a peak metal temperature (PMT) of 150 to 350° C., such as from 175 to 320° C., such as from 190 to 300° C., or even from 200 to 280° C. The film forming composition, when heat cured, may be cured at 210° C. or at 260° C. Curing the film forming composition forms the film forming layer described herein.

The substrate may optionally be subjected to other treatments prior to coating. For example, the substrate may be cleaned, cleaned and deoxidized, anodized, acid pickled, plasma treated, laser treated, or ion vapor deposition (IVD) treated. These optional treatments may be used on their own or in combination with a conversion composition.

At least a portion of the metal substrate surface may be cleaned and/or deoxidized and/or otherwise pretreated by any conventional means known in the art of cleaning or pretreating a metal substrate prior to contacting at least a portion of the substrate surface with the conversion coating composition, in order to remove grease, dirt, and/or other extraneous matter. At least a portion of the surface of the substrate may be cleaned by physical and/or chemical means, such as mechanically abrading the surface and/or cleaning/degreasing the surface with commercially available alkaline or acidic cleaning agents that are well known to those skilled in the art. Examples of acidic cleaners include PCL-452 (sulfuric acid based with surfactants) and ACC45SS (hydrofluoric acid based), which can be used as a two-part system and each of which are commercially available from PPG Industries, Inc. Such cleaners are often preceded or followed by a water rinse, such as with tap water, distilled water, deionized water, or combinations thereof.

As mentioned above, at least a portion of the cleaned substrate surface may be deoxidized, mechanically and/or chemically. As used herein, the term “deoxidize” means removal of the native oxide layer found on the surface of the substrate in order to promote uniform deposition of the conversion coating composition as well as to promote the adhesion of the film forming composition to the substrate surface. Suitable deoxidizers will be familiar to those skilled in the art. A typical mechanical deoxidizer may be uniform roughening of the substrate surface, such as by using a scouring or cleaning pad. Typical chemical deoxidizers include, for example, acid-based deoxidizers such as phosphoric acid, nitric acid, fluoroboric acid, sulfuric acid, chromic acid, hydrofluoric acid, ammonium bifluoride, or Amchem 7/17 deoxidizers (available from Henkel Technologies, Madison Heights, Mich.), OAKITE DEOXIDIZER LNC (commercially available from Chemetall), TURCO DEOXIDIZER 6 (commercially available from Henkel), Chemdeox 395 (fluorosilicic acid based), Chemdeox 400 (sulfuric acid, fluorosilicic acid and hydrofluoric acid based), Ultrax (AMC) 66 (commercially available from PPG Industries, Inc.) or combinations thereof. Often, the chemical deoxidizer comprises a carrier, often an aqueous medium, so that the deoxidizer may be in the form of a solution or dispersion in the carrier, in which case the solution or dispersion may be brought into contact with the substrate by any of a variety of known techniques, such as dipping or immersion, spraying, intermittent spraying, dipping followed by spraying, spraying followed by dipping, brushing, or roll-coating. According to the present invention, the skilled artisan will select a temperature range of the solution or dispersion, when applied to the metal substrate, based on etch rates, for example, at a temperature ranging from 50° F. to 150° F. (10° C. to 66° C.), such as from 70° F. to 130° F. (21° C. to 54° C.), such as from 80° F. to 120° F. (27° C. to 49° C.). The contact time may be from 30 seconds to 20 minutes, such as 1 minute to 15 minutes, such as 90 seconds to 12 minutes, such as 3 minutes to 9 minutes.

Following the cleaning and/or deoxidizing step(s), the substrate optionally may be rinsed with tap water, deionized water, and/or an aqueous solution of rinsing agents in order to remove any residue. The wet substrate surface may be pretreated by any method familiar to those skilled in the art of substrate protection, such an anodized or treated with a conversion coating composition, and/or may be treated one of the treatment compositions described above, or the substrate may be dried prior to treating the substrate surface, such as air dried, for example, by using an air knife, by flashing off the water by brief exposure of the substrate to a high temperature, such as 15° C. to 100° C., such as 20° C. to 90° C., or in a heater assembly using, for example, infrared heat, such as for 10 minutes at 70° C., or by passing the substrate between squeegee rolls.

The conversion coating composition and/or film forming composition may be applied to the metal substrate of the metal can, or a portion thereof, as a single layer or as part of a multi-layer system. The conversion coating composition may be applied as a single layer. The conversion coating composition may be applied as two or more layers. The conversion coating composition may be applied to an uncoated substrate. For the avoidance of doubt, an “uncoated substrate” includes a surface that is cleaned prior to application. The film forming composition may be applied as a single layer. The film forming composition may be applied as two or more layers. The film forming composition may be applied on top of another layer as part of a multi-layer system. For example, the film forming composition may be applied on top of a primer which is on top of the conversion coating layer. The film forming composition may form an intermediate layer or a top coat layer. The film forming composition may be applied as the first coat of a multi coat system. The film forming composition may be applied as an undercoat or a primer. The second, third, fourth etc. coats may comprise any suitable coating compositions such as those comprising, for example, polyvinyl chloride (PVC) resins, alkyd resins; polyolefin resins, epoxy resins; polyester resins; polyurethane resins; polysiloxane resins; hydrocarbon resins or combinations thereof. The second, third, fourth etc. coats may comprise polyester resins. The second, third, fourth etc. coats may be a liquid coating or a powder coating.

The conversion coating composition and/or film forming composition may be applied to the metal substrate before or after forming the metal can. For example, the conversion coating composition and/or film forming composition may be applied onto a can coil stock and then drawn into tubes, cans, or can lids (such as, without limitation, full aperture easy open ends). The conversion coating composition and/or film forming composition may be applied to the preformed metal can.

The coated metal cans of the present invention may demonstrate corrosion resistance and the hydrogen producing liquid sealed in such cans may demonstrate a reduction or prevention of as compared to metal cans that have not been treated as described herein.

The hydrogen sulfide producing liquid, when deposited in the coated metal can and sealed, may exhibit an average hydrogen sulfide concentration of less than 35 ppb, such as less than 20 or less than 10 ppb, using a gas detection tube method as described below for at least 2 months after the can is sealed. The average hydrogen sulfide concentration may be less than 5 ppb or even less than 1 ppb for at least 2 months after the metal can is sealed. The hydrogen sulfide producing liquid, when deposited in the coated metal can and sealed, may exhibit an average hydrogen sulfide concentration of less than 35 ppb, such as less than 20 or less than 10 ppb, using a gas detection tube method as described below for at least 3 months, for at least 4 months, for at least 5 months, for at least 6 months, for at least 7 months, for at least 8 months, for at least 9 months, for at least 10 months, for at least 11 months, or for at least 12 months after the can is sealed. As explained below, the concentrations of H₂S disclosed herein were determined by sparging the wine and measuring the effluent with a gas detection tube (Gastec 4LT, Japan) that was previously calibrated against sodium sulfide in wine.

The conversion coating compositions and/or the film forming compositions may be substantially free, may be essentially free or may be completely free of styrene. By “substantially free” in relation to styrene, it is meant that the film forming resin is formed from monomers which comprise less than 5 wt % of styrene based on the total weight of the monomers from which the film forming resin is formed. By essentially free in relation to styrene, is meant that the film forming resin is formed from monomers which comprise less than 1 wt % of styrene based on the total weight of the monomers from which the film forming resin is formed. By completely free in relation to styrene, is meant that the film forming resin is formed from monomers which comprise less than 0.01 wt % of styrene based on the total weight of the monomers from which the film forming resin is formed. The film forming resin may be formed from monomers which comprise no, i.e. 0 wt %, styrene based on the total weight of the monomers from which the film forming resin is formed.

The conversion coating compositions and/or the film forming compositions of the present disclosure may be substantially free, may be essentially free or may be completely free of bisphenol A (BPA) and derivatives thereof. Derivatives of bisphenol A include, for example, bisphenol A diglycidyl ether (BADGE). The conversion coating layer and/or the film forming layer of the present disclosure may also be substantially free, may be essentially free or may be completely free of bisphenol F (BPF) and derivatives thereof. Derivatives of bisphenol F include, for example, bisphenol F diglycidyl ether (BPFG). The compounds or derivatives thereof mentioned above may not be added to the composition intentionally but may be present in trace amounts because of unavoidable contamination from the environment. “Substantially free” refers to coating compositions, or components thereof, containing less than 1000 parts per million (ppm) of any of the compounds or derivatives thereof mentioned above. “Essentially free” refers to coating compositions, or components thereof, containing less than 100 ppm of any of the compounds or derivatives thereof mentioned above. By “completely free” refers to coating compositions, or components thereof, containing less than 20 parts per billion (ppb) of any of the compounds or derivatives thereof mentioned above.

The conversion coating compositions and/or the film forming compositions may be substantially free, may be essentially free or may be completely free of formaldehyde. “Substantially free” refers to coating compositions, or components thereof, containing less than 1000 parts per million (ppm) of formaldehyde. “Essentially free” refers to coating compositions, or components thereof, containing less than 100 ppm of any of formaldehyde. “Completely free” refers to coating compositions, or components thereof, containing less than 20 parts per billion (ppb) of formaldehyde.

For purposes of the detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers such as those expressing values, amounts, percentages, ranges, subranges and fractions may be read as if prefaced by the word “about,” even if the term does not expressly appear. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Where a closed or open-ended numerical range is described herein, all numbers, values, amounts, percentages, subranges and fractions within or encompassed by the numerical range are to be considered as being specifically included in and belonging to the original disclosure of this application as if these numbers, values, amounts, percentages, subranges and fractions had been explicitly written out in their entirety.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.

As used herein, unless indicated otherwise, singular encompasses plural and vice versa. For example, although reference is made herein to “a” Group VIB metal, “a” film forming resin, and the like, one or more of each of these and any other components can be used.

As used herein, “including,” “containing” and like terms are understood in the context of this application to be synonymous with “comprising” and are therefore open-ended and do not exclude the presence of additional undescribed or unrecited elements, materials, ingredients or method steps. As used herein, “consisting of” is understood in the context of this application to exclude the presence of any unspecified element, ingredient or method step. As used herein, “consisting essentially of” is understood in the context of this application to include the specified elements, materials, ingredients or method steps “and those that do not materially affect the basic and novel characteristic(s)” of what is being described.

As used herein, the terms “Group IA metal” and “Group IA element” refer to an element that is in Group IA of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63^(rd) edition (1983), corresponding to Group 1 in the actual IUPAC numbering.

As used herein, the term “Group IA metal compound” refers to compounds that include at least one element that is in Group IA of the CAS version of the Periodic Table of the Elements.

As used herein, the terms “Group IIA metal” and “Group IIA element” refer to an element that is in group IIA of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63^(rd) edition (1983), corresponding to Group 2 in the actual IUPAC numbering.

As used herein, the term “Group IIA metal compound” refers to compounds that include at least one element that is in Group IIA of the CAS version of the Periodic Table of the Elements.

As used herein, the terms “Group IIIB metal” and “Group IIIB element” refer to an element that is in Group IIIB of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63^(rd) edition (1983), corresponding to Group 3 in the actual IUPAC numbering.

As used herein, the term “Group IIIB metal compound” refers to compounds that include at least one element that is in Group IIIB of the CAS version of the Periodic Table of the Elements.

As used herein, the terms “Group IVA metal” and “Group IVA element” refer to an element that is in group IVA of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63^(rd) edition (1983), corresponding to Group 14 in the actual IUPAC numbering.

As used herein, the terms “Group IVA metal compound” refer to compounds that include at least one element that is in Group IVA of the CAS version of the Periodic Table of the Elements.

As used herein, the terms “Group IVB metal” and “Group IVB element” refer to an element that is in group IVB of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63^(rd) edition (1983), corresponding to Group 4 in the actual IUPAC numbering.

As used herein, the term “Group IVB metal compound” refers to compounds that include at least one element that is in Group IVB of the CAS version of the Periodic Table of the Elements.

As used herein, the terms “Group VB metal” and “Group VB element” refer to an element that is in group VB of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63^(rd) edition (1983), corresponding to Group 5 in the actual IUPAC numbering.

As used herein, the term “Group VB metal compound” refers to compounds that include at least one element that is in Group VB of the CAS version of the Periodic Table of the Elements.

As used herein, the terms “Group VIB metal” and “Group VIB element” refer to an element that is in group VIB of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63^(rd) edition (1983), corresponding to Group 6 in the actual IUPAC numbering.

As used herein, the term “Group VIB metal compound” refers to compounds that include at least one element that is in Group VIB of the CAS version of the Periodic Table of the Elements.

As used herein, the terms “Group VIIB metal” and “Group VIIB element” refer to an element that is in group VIIB of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63^(rd) edition (1983), corresponding to Group 7 in the actual IUPAC numbering.

As used herein, the term “Group VIIB metal compound” refers to compounds that include at least one element that is in Group VIIB of the CAS version of the Periodic Table of the Elements.

In addition, in this application, the use of “or” means “and/or” unless specifically stated otherwise, even though “and/or” may be explicitly used in certain instances.

As used herein, “including,” “containing” and like terms are understood in the context of this application to be synonymous with “comprising” and are therefore open-ended and do not exclude the presence of additional undescribed or unrecited elements, materials, ingredients or method steps. As used herein, “consisting of” is understood in the context of this application to exclude the presence of any unspecified element, ingredient or method step. As used herein, “consisting essentially of” is understood in the context of this application to include the specified elements, materials, ingredients or method steps “and those that do not materially affect the basic and novel characteristic(s)” of what is being described.

As used herein, the terms “on,” “onto,” “applied on,” “applied onto,” “formed on,” “deposited on,” “deposited onto,” mean formed, overlaid, deposited, or provided on but not necessarily in contact with the surface. For example, a film forming composition “deposited onto” a substrate does not preclude the presence of one or more other intervening coating layers of the same or different composition located between the film forming composition and the substrate.

As used herein, a “salt” refers to an ionic compound made up of cations and anions and having an overall electrical charge of zero. Salts may be hydrated or anhydrous.

As used herein, “composition” refers to a solution, mixture, or dispersion in a medium.

As used herein, a “coating composition” refers to a composition that, in an at least partially dried or cured state, is capable of producing a film, layer, or the like on at least a portion of a substrate surface.

As used herein, the term “dispersion” refers to a two-phase transparent, translucent or opaque system in which particles are in the dispersed phase and an aqueous medium, which includes water, is in the continuous phase.

As used herein, “deoxidizing composition” refers to a composition having a pH of no greater than 3.0 and a free fluoride content of no greater than 50 ppm based on total weight of the deoxidizing composition and that is capable of etching and/or reacting with and chemically altering a substrate surface.

As used herein, “deoxidizing composition bath” or “deoxidizing bath” refers to an aqueous bath containing a deoxidizing composition and that may contain components that are byproducts of the process.

As used herein, “cleaner composition” refers to a composition that removes oil, soil, and other contaminants from a substrate surface and that optionally is capable of etching or oxidizing the substrate surface.

As used herein, “cleaner composition bath” refers to an aqueous bath containing a cleaner composition and that may contain components that are byproducts of the process.

As used herein, “pretreatment composition” refers to a composition that is capable of reacting with and chemically altering the substrate surface and binding to it to form a film that affords corrosion protection.

As used herein, “pretreatment bath” refers to an aqueous bath containing a conversion composition and that may contain components that are byproducts of the process.

Also, the recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1, 2, 3, 4 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

As used herein, the term “cure” or “curing”, means that the components that form the composition are crosslinked to form a film, layer, or bond. As used herein, the term “at least partially cured” means that at least a portion of the components that form the composition interact, react, and/or are crosslinked to form a film, layer, or bond.

The terms “comprising”, “comprises” and “comprised of” as used herein are synonymous with “including”, “includes” or “containing”, “contains”, and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. Additionally, although the present invention has been described in terms of “comprising”, the coating compositions detailed herein may also be described as “consisting essentially of” or “consisting of”.

As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a list is described as comprising group A, B, and/or C, the list can comprise A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.

As used herein, the term “polymer” refers broadly to prepolymers, oligomers and both homopolymers and copolymers. It should be noted that the prefix “poly” refers to two or more.

Whereas specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.

Aspects

In view of the foregoing, the present invention thus relates in particular, without being limited thereto, to the following aspects:

-   -   Aspect 1. A metal can comprising         -   a conversion coating layer deposited on at least a portion             of an inside surface of the metal can, wherein the             conversion coating layer comprises a lanthanide series             element, a Group VIB metal, Group IIIB metal, a Group IVB             metal, and/or a homopolymer or copolymer comprising a             phosphorous-containing monomeric subunit m1 and optionally a             non-phosphorous-containing monomeric subunit m2;         -   a film-forming layer deposited on at least a portion of the             conversion coating layer; and         -   a hydrogen sulfide producing liquid deposited inside the             metal can.     -   Aspect 2. The metal can of Aspect 1, wherein the metal can         comprises aluminum, an aluminum alloy, and/or steel.     -   Aspect 3. The metal can of Aspect 2, wherein the metal can         comprises aluminum alloy.     -   Aspect 4. The metal can of any of the foregoing aspects, wherein         the lanthanide series element comprises lanthanum and/or cerium,         the Group VIB metal comprises chromium and/or molybdenum, Group         IIIB metal comprises yttrium, and the Group IVB metal comprises         zirconium, titanium, and/or hafnium.     -   Aspect 5. The metal can of any of the foregoing aspects, wherein         the Group IVB metal comprises zirconium.     -   Aspect 6. The metal can of Aspect 4, wherein the chromium         comprises chromium (III) and/or chromium (VI).     -   Aspect 7. The metal can of any of the foregoing aspects, wherein         the hydrogen sulfide producing liquid comprises wine, beer,         fruit juice, vinegar, cordial, coconut milk, soft drink, cider,         kombucha, or mead.     -   Aspect 8. The metal can of any of the foregoing aspects, wherein         the conversion coating layer has an average thickness of 0.001         msi to 0.05 msi as measured by ICP-OES.     -   Aspect 9. The metal can of any of the foregoing aspects, wherein         the film forming layer comprises an acrylic, a polyester, a         phenolic, a polyolefin, and/or an epoxy.     -   Aspect 10. The metal can of any of the foregoing aspects,         wherein the film forming layer comprises an emulsion polymerized         acrylic latex.     -   Aspect 11. The metal can of any of the foregoing aspects,         wherein the film forming layer has a dry film thickness of 2         microns to 20 microns as measured by a SENCON SI9600 Coating         Thickness Gauge.     -   Aspect 12. The metal can of any of the foregoing aspects,         wherein the conversion coating layer is on at least a portion of         a can body of the metal can.     -   Aspect 13. The metal can of any of the foregoing aspects,         wherein the conversion coating layer is on at least a portion of         a can end of the metal can.     -   Aspect 14. A metal can comprising         -   a conversion coating layer deposited on at least a portion             of the inside surface of the metal can, wherein the             conversion coating layer is deposited from a conversion             coating composition comprising a lanthanide series element,             a Group VIB metal, Group IIIB metal, a Group IVB metal,             and/or a homopolymer or copolymer comprising a             phosphorous-containing monomeric subunit m1 and optionally a             non-phosphorous-containing monomeric subunit m2;         -   a film-forming layer deposited on at least a portion of the             conversion coating layer; and         -   a hydrogen sulfide producing liquid inside the metal can.     -   Aspect 15. The metal can of Aspect 14, wherein the metal can         comprises aluminum, aluminum alloy, and/or steel.     -   Aspect 16. The metal can of Aspect 15, wherein the metal can         comprises aluminum alloy.     -   Aspect 17. The metal can of Aspect 14 to 16, wherein the Group         IVB metal comprises hexafluorozirconic acid.     -   Aspect 18. The metal can of Aspects 14 to 17, wherein the         conversion coating composition further comprises a source of         phosphate ions.     -   Aspect 19. The metal can of Aspect 18, wherein the source of         phosphate ions comprises phosphoric acid.     -   Aspect 20. The metal can of Aspects 18 or 19, wherein the source         of phosphate ions is in an amount of 2 ppm to 300 ppm.     -   Aspect 21. The metal can of Aspects 14 to 20, wherein the         conversion coating composition further comprises a source of         free fluoride.     -   Aspect 22. The metal can of Aspect 21, wherein the source of         free fluoride comprises hydrofluorosilicic acid and fluoboric         acid.     -   Aspect 23. The metal can of Aspects 21 or 22, wherein the source         of free fluoride is in an amount of 5 ppm to 300 ppm.     -   Aspect 24. The metal can of Aspects 14 to 23, wherein the Group         IVB metal comprises a source of free fluoride.     -   Aspect 25. The metal can of Aspects 14 to 24, wherein the         conversion coating composition further comprises an         electropositive metal.     -   Aspect 26. The metal can of Aspect 25, wherein the         electropositive metal is in an amount of 2 ppm to 150 ppm, based         on a total weight of the ingredients in the conversion coating         composition.     -   Aspect 27. The metal can of Aspect 25 or 26, wherein the         electropositive metal comprises copper nitrate.     -   Aspect 28. A method of packaging a hydrogen sulfide producing         liquid in a metal can, the method comprising         -   depositing the hydrogen sulfide producing liquid inside the             metal can,         -   wherein the metal can comprises             -   a conversion coating layer deposited on at least a                 portion of the inside surface of the metal can, wherein                 the conversion coating layer comprises a lanthanide                 series element, a Group VIB metal, a Group IIIB metal,                 and/or a Group IVB metal, and/or a homopolymer or                 copolymer comprising a phosphorous-containing monomeric                 subunit m1 and optionally a non-phosphorous-containing                 monomeric subunit m2; and         -   a film-forming layer deposited on at least a portion of the             conversion coating layer.     -   Aspect 29. The method of Aspect 28, wherein the conversion         coating layer is formed by a conversion coating composition         comprising the lanthanide series element, the Group VIB metal,         the Group IIIB metal, the Group IVB metal, and/or a homopolymer         or copolymer comprising a phosphorous-containing monomeric         subunit m1 and optionally a non-phosphorous-containing monomeric         subunit m2.     -   Aspect 30. The method of Aspect 29, wherein the conversion         coating composition comprises an electropositive metal, a source         of phosphate ions, and/or a source of free fluoride.     -   Aspect 31. The method of Aspect 29, wherein the Group IVB metal         comprises hexafluorozirconic acid.     -   Aspect 32. The method of Aspect 30, wherein the source of         phosphate ions comprises phosphoric acid.     -   Aspect 33. The method of Aspects 30 or 32, wherein the source of         phosphate ions is in an amount of 2 ppm to 300 ppm.     -   Aspect 34. The method of Aspect 30, wherein the source of free         fluoride comprises hydrofluorosilicic acid and fluoboric acid.     -   Aspect 35. The method of Aspects 30 or 34, wherein the source of         free fluoride is in an amount of 5 ppm to 300 ppm.     -   Aspect 36. The method of Aspects 28 to 35, wherein the Group IVB         metal comprises a source of free fluoride.     -   Aspect 37. The method of Aspect 30, wherein the electropositive         metal is in an amount of 2 ppm to 150 ppm, based on a total         weight of the ingredients in the conversion coating composition.     -   Aspect 38. The method of Aspect 30 or 37, wherein the         electropositive metal comprises copper nitrate.     -   Aspect 39. A metal can comprising         -   a conversion coating layer deposited on at least a portion             of an internal surface of the metal can, the conversion             coating layer comprising a lanthanide series element, a             Group VIB metal, Group IIIB metal, a Group IVB metal, and/or             a homopolymer or copolymer comprising a             phosphorous-containing monomeric subunit m1 and optionally a             non-phosphorous-containing monomeric subunit m2;         -   a film forming layer deposited on at least a portion of the             conversion coating layer; and         -   a hydrogen sulfide producing liquid inside the metal can,             wherein the hydrogen sulfide producing liquid exhibits a             hydrogen sulfide concentration of less than 35 ppb as             measured by a gas detection tube for at least two months             after the metal can is sealed.     -   Aspect 40. The metal can of Aspect 39, wherein the metal can         comprises aluminum, aluminum alloy, and/or steel.     -   Aspect 41. The metal can of Aspect 40, wherein the metal can         comprises aluminum alloy.     -   Aspect 42. The metal can of Aspects 39 to 41, wherein the         lanthanide series element comprises lanthanum and/or cerium, the         Group VIB metal comprises chromium and/or molybdenum, Group IIIB         metal comprises yttrium, and the Group IVB metal comprises         zirconium, titanium, and/or hafnium.     -   Aspect 43. The metal can of Aspects 39 to 42, wherein the Group         IVB metal comprises zirconium.     -   Aspect 44. The metal can of Aspect 42, wherein the chromium         comprises chromium (III) and/or chromium (VI).     -   Aspect 45. The metal can of Aspects 39 to 44, wherein the         hydrogen sulfide producing liquid deposited in the metal can         comprises wine, beer, fruit juice, vinegar, cordial, coconut         milk, soft drink, cider, kombucha, or mead.     -   Aspect 46. The metal can of Aspects 39 to 45, wherein the         average thickness of the conversion coating layer on the metal         can is 0.001 msi to 0.05 msi as measured by ICP-OES.     -   Aspect 47. The metal can of Aspects 39 to 46, wherein the film         forming layer comprises an acrylic, a polyester, a phenolic, a         polyolefin, and/or an epoxy.     -   Aspect 48. The metal can of Aspects 39 to 47, wherein the film         forming layer has a thickness of 1 msi to 4 msi as measured by a         SENCON S19600 Coating Thickness Gauge.     -   Aspect 49. The metal can of Aspects 39 to 48, wherein the         conversion coating layer is on at least a portion of a can body         of the metal can.     -   Aspect 50. The metal can of Aspects 39 to 49, wherein the         conversion coating layer is on at least a portion of a can end         of the metal can.     -   Aspect 51. A system for treating a metal can for packaging a         hydrogen sulfide producing liquid, the system comprising         -   a conversion coating layer deposited on at least a portion             of the inside surface of the metal can, wherein the             conversion coating layer comprises a lanthanide series             element, a Group VIB metal, a Group IIIB metal, a Group IVB             metal, and/or a homopolymer or copolymer comprising a             phosphorous-containing monomeric subunit m1 and optionally a             non-phosphorous-containing monomeric subunit m2; and         -   a film-forming layer deposited on at least a portion of the             conversion coating layer.     -   Aspect 52. The metal can of Aspect 51, wherein the metal can         comprises aluminum, aluminum alloy, and/or steel.     -   Aspect 53. The metal can of Aspect 52, wherein the metal can         comprises aluminum alloy.     -   Aspect 54. The metal can of Aspects 51 to 53, wherein the metal         can further comprises a hydrogen sulfide producing liquid         deposited inside the metal can.     -   Aspect 55. The metal can of Aspects 51 to 54, wherein the         conversion coating layer comprises zirconium.     -   Aspect 56. The metal can of Aspect 51, wherein the chromium         comprises chromium (III) and/or chromium (VI).     -   Aspect 57. The metal can of Aspects 54 to 56, wherein the         hydrogen sulfide producing liquid deposited in the metal can         comprises wine, beer, fruit juice, vinegar, cordial, coconut         milk, soft drinks, cider, kombucha, or mead.     -   Aspect 58. The metal can of Aspects 51 to 57, wherein the         average thickness of the conversion coating layer on the metal         can is 0.001 msi to 0.05 msi as measured by ICP-OES.     -   Aspect 59. The metal can of Aspects 51 to 58, wherein the film         forming layer comprises an acrylic, a polyester, a phenolic, a         polyolefin, and/or an epoxy.     -   Aspect 60. The metal can of Aspects 51 to 59, wherein the film         forming layer has a thickness of 1 msi to 4 msi as measured by a         SENCON SI9600 Coating Thickness Gauge.     -   Aspect 61. The metal can of Aspects 51 to 60, wherein the         conversion coating layer is on at least a portion of a can body         of the metal can.     -   Aspect 62. The metal can of Aspects 51 to 61, wherein the         conversion coating layer is on at least a portion of a can end         of the metal can.

All of the features contained herein may be combined with any of the above aspects in any combination.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the following examples.

EXAMPLES Example 1: Zirconium Based Conversion Coating Panel Preparation

Two sets of aluminum panels (un-drawn can body stock) were cleaned with isopropanol to remove any manufacturing oils. A zirconium pre-treatment (Table 1) was then applied to one set of panels according to the sequence in Table 2. The aluminum substrate was placed on a racking system where it entered a first stage containing an array of impingement spray nozzles spraying an alkaline etchant and surfactant cleaner 2K package (available from PPG Industries, Inc. as DR1369M and DR1700).

The panels then continued into stage 2, where the alkaline etchant was removed via a low pH acid rinse with rows of flood nozzles, followed by stage 3 of a city water rinse to remove the acid.

Next, in stage 4, hollowcone nozzles sprayed the acidic zirconium conversion coating composition set forth in Table 1, which deposits a thin layer of zirconium oxyhydroxide on the panel surface. Lastly, in stage 5, the panels are rinsed with deionized water, before being dried with infrared (IR) heaters.

The second set of panels did not receive any pre-treatment. Afterwards, a commercial internal varnish, an acrylic latex lacquer sold commercially by PPG Industries, Inc. under the tradename PPG Innovel® 2012-823, was applied to both sets of panels by drawing down the wet coating using a number #20 wire bar. The coated substrate panels were baked at 193° C. for three minutes. The cured film had a nominal thickness of 4-5 mg/in2 as determined by a SENCON SI9600 Coating Thickness Gauge.

Testing for H₂S Generation

The prepared panels were tested for H₂S gas production in wine by placing the panels in Sieg-mi-flex extraction cells (LABC-Labortechnik, Germany), such that 1 dm² of panel was in contact with 100 mL of wine. The cells were then filled with wine (pH 3.3) (sold by Barefoot Cellars under the tradename Barefoot® Refresh® Crisp White Spritzer, USA) spiked with 50 ppm sodium metabisulfite and held at 50° C. in a hot room for 10 days (representative of 2-3 months on the shelf at room temperature). After the 10 days, the cells were removed from the hot room, allowed to cool to room temperature, and then the concentration of H₂S was determined by sparging the wine and measuring the effluent with a gas detection tube (Gastec 4LT, Japan) that was previously calibrated against sodium sulfide in wine. After measuring the samples in triplicate, the wine in contact with the pre-treated panels had an average H₂S concentration of 23 ppb and the non-pre-treated panels had an H₂S concentration of 40 ppb.

TABLE 1 Zr Conversion coating composition % Substance (w/w) COPPER NITRATE SOLUTION 0.22 18%(1729)/COPPER NITRATE SOLUTION PHOSPHORIC ACID 75%/ 0.08 PHOSPHORIC ACID 75% (53 BE ) HEXAFLUOROZIRCONIC ACID 1.507 45%/HEXAFLUOROZIRCONIUM ACID 45% DEIONIZED WATER/DEIONIZED 98.649 WATER

TABLE 2 Pretreatment Application Conditions Stage 1—Cleaner/Etchant Etchant DR1369M Surfactant DR1700 pH 12 DR1700 700 ppm concentration Temperature 110-115° F. Time 20 seconds Stage 2—Acid Rinse pH 2 Temperature Ambient Time 20 seconds Stage 3—City Water pH 7 Temperature Ambient Time 20 seconds Stage 4—Conversion Conversion ZB4200 Coating pH 4.5 Temperature 120° F. Time 45 seconds Pressure 9 PSI Concentration 3.00% Stage 5—DI Rinse pH 5.5 Conductivity 7 μs Temperature Ambient Time 20 seconds

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. 

1. A metal can comprising: a conversion coating layer deposited on at least a portion of the inside surface of the metal can, wherein the conversion coating layer comprises a lanthanide series element, a Group VIB metal, a Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; a film-forming layer deposited on at least a portion of the conversion coating layer; and a hydrogen sulfide producing liquid deposited inside the metal can.
 2. The metal can of claim 1, wherein the metal can comprises aluminum, aluminum alloy, and/or steel.
 3. The metal can of claim 1, wherein the homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2 comprises a homopolymer, a dipolymer and/or a terpolymer, the lanthanide series element comprises lanthanum and/or cerium, the Group VIB metal comprises chromium and/or molybdenum, Group IIIB metal comprises yttrium, and the Group IVB metal comprises zirconium, titanium, and/or hafnium.
 4. The metal can of claim 1, wherein the Group IVB metal comprises zirconium.
 5. The metal can of claim 3, wherein the chromium comprises chromium (III) and/or chromium (VI).
 6. The metal can of claim 1, wherein the hydrogen sulfide producing liquid deposited in the metal can comprises wine, beer, fruit juice, vinegar, cordial, coconut milk, soft drink, cider, kombucha, or mead.
 7. The metal can of claim 1, wherein the average thickness of the conversion coating layer on the metal can is 0.001 msi to 0.05 msi.
 8. The metal can of claim 1, wherein the film forming layer comprises an acrylic, a polyester, a phenolic, a polyolefin, and/or an epoxy.
 9. The metal can of claim 1, wherein the film forming layer has a dry film thickness of 2 microns to 20 microns.
 10. The metal can of claim 1, wherein the conversion coating layer is on at least a portion of a can body of the metal can.
 11. The metal can of claim 1, wherein the conversion coating layer is on at least a portion of a can end of the metal can.
 12. The metal can of claim 1, wherein the conversion coating layer is deposited from a conversion coating composition comprising the lanthanide series element, the Group VIB metal, the Group IIIB metal, the Group IVB metal, and/or the homopolymer or copolymer comprising the phosphorous-containing monomeric subunit m1 and optionally the non-phosphorous-containing monomeric subunit m2.
 13. The metal can of claim 12, wherein the Group IVB metal is hexafluorozirconic acid.
 14. The metal can of claim 12, wherein the conversion coating composition further comprises a source of phosphate ions.
 15. The metal can of claim 14, wherein the source of phosphate ions comprises phosphoric acid.
 16. The metal can of claim 12, wherein the conversion coating composition further comprises a source of free fluoride.
 17. The metal can of claim 12, wherein the conversion coating composition further comprises an electropositive metal.
 18. The metal can of claim 12, wherein the Group IVB metal in the conversion coating composition comprises a source of free fluoride.
 19. A method of packaging a hydrogen sulfide producing liquid in a metal can, the method comprising: depositing the hydrogen sulfide producing liquid inside the metal can, wherein the metal can comprises: a conversion coating layer deposited on at least a portion of the inside surface of the metal can, wherein the conversion coating layer comprises a lanthanide series element, a Group VIB metal, a Group IIIB metal, a Group IVB metal, and/or a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit m1 and optionally a non-phosphorous-containing monomeric subunit m2; and a film-forming layer deposited on at least a portion of the conversion coating layer.
 20. The metal can of claim 1, wherein the hydrogen sulfide producing liquid exhibits a hydrogen sulfide concentration of less than 35 ppb as measured by a gas detection tube for at least two months after the metal can is sealed. 